The Chilicon Power (chiliconpower.com) CP-250E Microinverter now has the ability to AC couple with battery inverter and backup generator systems through Freq-Watt and Volt-Watt Control Modes. Chilicon’s new dual mode system simplifies, streamlines, and lowers cost, providing a next-gen solution to the problems most often associated with conventional AC systems. This builds on Chilicon’s existing Zero-Net Export (Self-Supply Mode) capability which uses CT-Clamps in conjunction with the company’s CP-100 Gateway to enable customers to match their own load, but not export to the grid.
Chilicon’s co-founder Chris Jones emphasizes, “The CP-250E was designed to overcome the challenges presented by AC coupling, and the incompatibilities between disparate manufacturers.”
For years, experts have agreed that AC-and DC-coupled systems each offered advantages and challenges. Some said that AC coupling provided higher system efficiency, ability to use smaller array wire and fewer DC components. But, during a utility outage, overcharging of batteries caused by surplus energy was a risk. Back in 2012, one article by Frank Andorka in Solar Power World Online stated that, “some battery-based inverter manufacturers attempted to simplify [their invention] by altering the frequency.” However, altering the frequency often caused instability.
While some manufacturers overcame the risks of AC coupling during a retro-fit, many could not eliminate 1) low efficiency, 2) high cost, 3) installation complexity and 4) warranty implications. But today, Chilicon’s system has met the challenge with these two new features:
In AC coupled applications the microinverters effectively synchronize with a battery inverter to convert unused AC energy to DC in order to charge batteries. During off-grid operation, battery inverters that are able to slew output frequency can control CP250E output power with a linear roll-off between mutually agreed Start and Stop frequencies. This allows the microinverters to be controlled by the battery inverter such that the batteries maintain optimal charge during daylight running hours.
To safely parallel with a generator, the CP-250E provides a Volt-Watt mode in which line voltage rise is constantly monitored by each inverter and power will be linearly decreased between preset start and stop voltage thresholds. This prevents an over-voltage condition from developing on an islanded generator controlled system and allows the microinverter array to co-generate (decreasing fuel consumption) without need for a transfer switch between the generator and the array.
Both modes can be programmed into any existing or newly installed Chilicon Power microinverter systems using the full-color touch controlled CP-100 Gateway.
The CP-250E microinverter provides continuous output power up to 289 Watts (13 units per 20A branch circuit) on 240Volt split phase systems and up to 277 Watts (12 units per 20A branch circuit) on 208 three phase systems. The device can be paired with 60 cell modules. Power control under Freq/Volt Watt modes may only be enabled when paired with 60 cell modules.
CP-250E and CP-100 effectively bypasses the need for installers to create their own – often less efficient – solutions.
According to Chilicon co-founder Alexandre Kral: “The Singular efficiency of the CP-250E is embodied in its long-life, reliable charge controlling enabled by Frequency-Watt Mode and Volt-Watt Mode developed by Chilicon for the CP-250E.”
Application notes and datasheets can be found at: http://www.chiliconpower.com/resources/download-libraries